1. Field of the Invention
The invention relates to a gearbox for a drive arrangement of a machine for driving the machine with variably adjustable rotational speed and to a drive arrangement with a gearbox and a machine to be driven with a variably adjustable rotational speed.
2. Description of the Related Art
From practice, applications are known in which a machine such as a compressor or a pump have to be operated with a variably adjustable rotational speed. According to practice, either electric motors with frequency converters are employed as drive units or a gearbox with a hydraulically or electrically driven speed modulation branch is employed, with which a transmission that is variable in the required range can be provided. Both possibilities for driving a machine with variably adjustable rotational speed known from practice are involved and expensive because of the high power outputs required for the driving task, medium-voltage frequency converters are necessary.